In the Dummit-Foote text the definition of relation and presentation (Group theory) are introduced as:
In connection with the above definition I wounder what should be the presentation of $\mathbb Z$? Clearly enough here the generating set $S=\{1\}.$ But I'm clueless about the set of equation(s) $R_i$ in $\{1,0\}$ so that $\mathbb Z$ can be presented as:
$$\mathbb Z=\langle 1:R_i\rangle$$

$\mathbb Z$ is the free group on one generator - free groups have generators but no relations. You could say that the set of relations is empty.